package com.chinathinks.core.net;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.BufferedOutputStream;
import java.io.DataOutputStream;

/***
 * The FingerClient class implements the client side of the Internet Finger
 * Protocol defined in RFC 1288. To finger a host you create a FingerClient
 * instance, connect to the host, query the host, and finally disconnect from
 * the host. If the finger service you want to query is on a non-standard port,
 * connect to the host at that port. Here's a sample use:
 * 
 * <pre>
 * FingerClient finger;
 * 
 * finger = new FingerClient();
 * 
 * try {
 * 	finger.connect(&quot;foo.bar.com&quot;);
 * 	System.out.println(finger.query(&quot;foobar&quot;, false));
 * 	finger.disconnect();
 * } catch (IOException e) {
 * 	System.err.println(&quot;Error I/O exception: &quot; + e.getMessage());
 * 	return;
 * }
 * </pre>
 * <p>
 * <p>
 * 
 * @author Daniel F. Savarese
 ***/

public class FingerClient extends SocketClient {
	/***
	 * The default FINGER port. Set to 79 according to RFC 1288.
	 ***/
	public static final int DEFAULT_PORT = 79;

	private static final String __LONG_FLAG = "/W ";

	private transient StringBuffer __query = new StringBuffer(64);
	private transient char[] __buffer = new char[1024];

	/***
	 * The default FingerClient constructor. Initializes the default port to
	 * <code> DEFAULT_PORT </code>.
	 ***/
	public FingerClient() {
		setDefaultPort(DEFAULT_PORT);
	}

	/***
	 * Fingers a user at the connected host and returns the output as a String.
	 * You must first connect to a finger server before calling this method, and
	 * you should disconnect afterward.
	 * <p>
	 * 
	 * @param longOutput
	 *            Set to true if long output is requested, false if not.
	 * @param username
	 *            The name of the user to finger.
	 * @return The result of the finger query.
	 * @exception IOException
	 *                If an I/O error occurs while reading the socket.
	 ***/
	public String query(boolean longOutput, String username) throws IOException {
		int read;
		StringBuffer result = new StringBuffer(__buffer.length);
		BufferedReader input;

		input = new BufferedReader(new InputStreamReader(getInputStream(longOutput, username)));

		while (true) {
			read = input.read(__buffer, 0, __buffer.length);
			if (read <= 0)
				break;
			result.append(__buffer, 0, read);
		}

		input.close();

		return result.toString();
	}

	/***
	 * Fingers the connected host and returns the output as a String. You must
	 * first connect to a finger server before calling this method, and you
	 * should disconnect afterward. This is equivalent to calling
	 * <code> query(longOutput, "") </code>.
	 * <p>
	 * 
	 * @param longOutput
	 *            Set to true if long output is requested, false if not.
	 * @return The result of the finger query.
	 * @exception IOException
	 *                If an I/O error occurs while reading the socket.
	 ***/
	public String query(boolean longOutput) throws IOException {
		return query(longOutput, "");
	}

	/***
	 * Fingers a user and returns the input stream from the network connection
	 * of the finger query. You must first connect to a finger server before
	 * calling this method, and you should disconnect after finishing reading
	 * the stream.
	 * <p>
	 * 
	 * @param longOutput
	 *            Set to true if long output is requested, false if not.
	 * @param username
	 *            The name of the user to finger.
	 * @return The InputStream of the network connection of the finger query.
	 *         Can be read to obtain finger results.
	 * @exception IOException
	 *                If an I/O error during the operation.
	 ***/
	public InputStream getInputStream(boolean longOutput, String username) throws IOException {
		DataOutputStream output;

		__query.setLength(0);
		if (longOutput)
			__query.append(__LONG_FLAG);
		__query.append(username);
		__query.append(SocketClient.NETASCII_EOL);

		output = new DataOutputStream(new BufferedOutputStream(_output_, 1024));
		output.writeBytes(__query.toString());
		output.flush();

		return _input_;
	}

	/***
	 * Fingers the connected host and returns the input stream from the network
	 * connection of the finger query. This is equivalent to calling
	 * getInputStream(longOutput, ""). You must first connect to a finger server
	 * before calling this method, and you should disconnect after finishing
	 * reading the stream.
	 * <p>
	 * 
	 * @param longOutput
	 *            Set to true if long output is requested, false if not.
	 * @return The InputStream of the network connection of the finger query.
	 *         Can be read to obtain finger results.
	 * @exception IOException
	 *                If an I/O error during the operation.
	 ***/
	public InputStream getInputStream(boolean longOutput) throws IOException {
		return getInputStream(longOutput, "");
	}

}
